For the purposes of automatic identification, a product item is commonly identified by a 12-digit Universal Product Code (UPC), encoded machine-readably in the form of a printed bar code.
Within supply chain management, there is considerable interest in expanding or replacing the UPC scheme to allow individual product items to be uniquely identified and thereby tracked. Individual item tagging can reduce “shrinkage” due to lost, stolen or spoiled goods, improve the efficiency of demand-driven manufacturing and supply, facilitate the profiling of product usage, and improve the customer experience.
There are two main contenders for individual item tagging: optical tags in the form of two-dimensional bar codes, and radio frequency identification (RFID) tags. Optical tags have the advantage of being inexpensive, but require optical line-of-sight for reading. RFID tags have the advantage of supporting omnidirectional reading, but are comparatively expensive.